Middle-East Journal of Scientific Research 25 (1): 181-191, 2017 ISSN 1990-9233 © IDOSI Publications, 2017 DOI: 10.5829/idosi.mejsr.2017.181.191

Tiger Hash Attribute Encryption for Secured Cloud Service Provisioning

12P. Muthusamy and V. Murali Bhaskaran

1Department of Computer Science & Engg, Anna University, Chennai - 600 025, Tamil Nadu, India 2Principal, Dhirajlal Gandhi College of Technology, Salem - 636 309, Tamil Nadu, India

Abstract: Cloud Computing facilitates organization to share various operation services in a high secure manner. In cloud based communication, the confidentiality of the systemis the major concern. Hence, the secured message communication is to prevent unauthorized access of confidential information. Several encryption approacheshave been developed for cloud service provisioning. But, cloud users still have major security and confidentiality about their outsourced data due to unauthorized access within the service providers. In order to improve the confidentiality in cloud service provisioning, Tiger Cryptographic Hash Function based Attribute Encryption and Decryption (TCHF-AED) technique is introduced. Tiger is a cryptographic hash function for achieving higher confidentiality rate in cloud service provisioning. Initially, the attribute cloud request is sent from the users to cloud server. Next, Tiger Cryptographic Hash Function is used to achieve cloud data confidentiality based on output of hash value.TheAttribute Encryption is performed for converting actual message into cipher textand the hash value of each encrypted message is calculated. The encrypted message with hash value is stored in cloud server. Whenever the cloud user accesses the data from cloud server, the hash value is recomputed to achieve the correctness of the message. If the correctness is achieved the decryption is performed to attain the confidentiality. The Attribute Decryption is carried out to decrypt the cipher text and achievean original message. This helps to improve the confidentiality rate and reduces the communication overhead. Experimental results shows that the proposed TCHF-AED technique achieves better performance in terms of Communication overhead, encryption time, memory consumption and confidentiality rate compared to the state-of-the-art works.

Key words: Cloud service provisioning Cloud users Tiger Cryptographic Hash Function Attribute Encryption Attribute Decryption Cipher text

INTRODUCTION

Cloud computing is a one of the Internet-based computing that offers services to computer and other cloud devices. The most significant concern is a security in cloud implementation. The confidentiality based communication between the cloud user and service provider is essential in secured data communication. Confidentiality refers to maintenance data privacy. In cloud computing, the users send the request to server and Fig. 1: Block diagram of data communication in cloud it response the user requested data. During data communication, security is the major role in service Figure 1 illustrates the block diagram of cloud data provisioning in order to achieve the higher confidentiality. communication. The cloud user sends the request to The basic diagram of the message communication cloud server. The third- party auditor is a partially trusted between clients and server is shown in Figure 1. and independent entity that can provide access and

Corresponding Author: P. Muthusamy, Research Scholar, Department of Computer Science & Engg., Anna University, Chennai - 600 025, Tamil Nadu, India. 181 Middle-East J. Sci. Res., 25 (1): 181-191, 2017 mediation if essential. The cloud users interact with cloud To improve the security in cloud service server for accessing secured communication. provisioning, Tiger Cryptographic Hash Function Confidentiality is also maintained by technical tools such based Attribute Encryption and Decryption (TCHF- as encryption, access control and authorized security. AED) technique is introduced Therefore, the various encryption techniques were In order to convert the original message into cipher developed for secure communication. A Key-policy text, Attribute Encryption is performed by checking attribute-based encryption (KP-ABE) was introduced in the authorization cloud data owner and cloud data [1] which allows senders to encrypt messages based on requester. a set of attributes. However, security and confidentiality In order to improve confidentiality, the correctness of about their outsourced data are not yet improved. the data is measured using the hash value Mediated certificate less public key encryption Finally, the TCHF-AED technique performs dynamic (mCL-PKE) was introduced in [2] to resolve the key attribute decryption whenever a cloud user requests escrow difficulty in identity based encryption and for the corresponding message with the help of certificate revocation. While handling multiple users, the secret key. overall overhead is increased. An attribute-based secure data sharing method was The rest of the paper is structured as follows: In introduced in [3] with Efficient revocation (EABDS) in Section 2, Tiger Cryptographic Hash Function based cloud computing using symmetric key encryption which Attribute Encryption and Decryption (TCHF-AED) improves the data confidentiality. A novel encrypting technique is described with neat diagram. In Section 3, algorithm based on symmetric key cryptographic experimental settings are provided with the analysis of framework was introduced in [4]. However, it reduced the results explained in Section 4. In Section 5, introduces the reliability of the encryption. Secure Service Provisioning related works. The conclusion of the research work is architecture was designed in [5] for Cyber Physical Cloud presented in section 6. Computing Systems provided as service provisioning sub systems. Though, the system confidentiality is remained Tiger Cryptographic Hash Function Based Attribute unaddressed. A smart card generator (SCG) was Encryption and Decryption: Tiger cryptographic hash introduced in [6] for decreasing the authentication function is used for improving the security in cloud processing time used by message communication service provisioning. In cryptography, Tiger is a one of between cloud service providers and users. A secure the cryptographic hash function which has effectiveness mobile Web service framework was designed in [7] for on 64-bit platforms. The tiger hash value size is secure and private mobile cloud in order to provide the characterized as 192 bits. Hence, the size of the tiger hash Web services and improves the service performance. value is adaptability for improving the security in cloud A Comprehensive Transmission (CT) model was service provisioning. Tiger is a modification where the introduced in [8] by combining the Client/Server (C/S) message is protected by first adding a byte with the mode and the Peer-to-Peer (P2P) mode for reliable data hexadecimal value of 0x01 with the use of Tiger hash transmission and secure services in cloud computing. function. Tiger is mostly used in the structure of Merkle An Elliptic Curve Cryptography (ECC) technique was hash tree, where it is specified as TTH (Tiger Tree Hash). introduced in [9] provides solutions for secured Cloud TTH is utilized by several clients on the data environment. Though, the technique failed to consider the communication networks. Based on the above confidence measure in both large and small scale specification, the tiger hash function is constructed in organization. Global Authentication Register System order to achieve confidentiality in message (GARS) was developed in [10] to decrease cloud material communication. Due to rapid growth of transaction risk and improve the security and performance. The issues processing in cloud, maintaining the security level in presented in the existing literature such as lesser service provisioning is a significant to hide the original reliability, higher overhead, lack of confidence measure. In message. Therefore, the security is enhanced using Tiger order to address such kind of issues, an efficient Tiger Cryptographic Hash Function based Attribute Encryption Cryptographic Hash Function based Attribute Encryption and Decryption (TCHF-AED) technique. The TCHF-AED and Decryption (TCHF-AED) technique is developed in technique provides high secure message communication cloud service provisioning. across different attributes. The communication is The objective of the research work is described as performed effectively in TCHF-AED technique on cloud follows, data storage system by different users through various

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Tiger Cryptographic Hash Function: Tiger is a cryptographic hash function structured by the universal Merkle-Damgard paradigm. This is the one-way compression function which functioned on 64-bit architecture. The Tiger hash function is operated based on universal Merkle-Damgard hash function. The 64-bit words, managing 3 words of state and processing 9 words of data is functioned by the compression function. There are 27 rounds using a combination of operation with XOR, addition/subtraction, rotations, s box lookups and a comparatively complex key scheduling algorithm for developing 27 round keys from the 9 input words. The 512 bit input fetches 192 bit hash value in tiger hashing process. The resultant hash value has high confidence. Tiger/128 and Tiger/160 constructs a hash Fig. 2: Architecture diagram of the Tiger Cryptographic length of 128 and 160 bits, correspondingly, to provide Hash Function based Attribute Encryption and compatibility. The tiger hash function is used for secured Decryption cloud service provisioning and also achieving the higher confidentiality rate. The confidentiality is to guarantee the access levels. Different attribute request = { ttr12, attr system only the authorized user receives the message

,..., ttrn from the clients for performing the data from cloud server. communication. Figure 2 shows the architecture diagram Tiger Cryptographic hash function is selected in of the tiger Cryptographic Hash Function for providing TCHF-AED technique to make security in cloud service the secured response from server to client based on the provisioning. Tiger is recent hash function designed on encryption and decryption. Initially, the client request is fast 64-bit processor and it has 48 hexadecimal digit of the number of attributes = { ttr12, attr ,..., ttrn is sent to hash length. Tiger cryptographic hash function takes an cloud server. The attributes requests from the clients for input as message block. A hash function obtains any performing message communication. The requested input string and produces a fixed output length string attribute is only made visible from the cloud storage with which is called as hash value. high security level from the cloud server. Figure 3 shows the structure of Tiger Cryptographic As shown in Figure, the attribute 1 2, 3...n are Hash Function and the input is the message block requested from the clients. As a result, the attribute (i.e. attributes file size) which is designed a one-way information from database is handled to fetch the function. The only way to reconstruct the input data from requested information. After that, tiger hash function is a Tiger Cryptographic Hash Function to generate a hash used to calculate the hash value in order to achieve the value output which has fixed size. The property of hash confidentiality. Followed by the attributes encryption and function is collision resistance in which the attackers are decryption is carried out to achieve higher confidentiality restricted to access the cloud data by having the hash protected executions. Finally, the client system achieves value. Therefore, collision resistance is also known as the requested result with high security level. Each collision free hash function. The output of the tiger hash message communication is equipped with higher function is a fixed size, there is no collision exists between confidentiality rate. Furthermore, the cloud data storage hash function. provides high services to improve the message communication in cloud service provisioning. Therefore, Tiger Hash Function Based Attribute Encryption and this helps to improve the confidentiality rate in cloud Decryption: In Tiger Cryptographic Hash Function, the service provisioning. Confidentiality is the ability of unencrypted data is denoted as plaintext. Plain text is an system to ensure that unknown can read the message original user message. For performing the attribute apart from the specified receiver in cloud environment. encryption, the plain text is converted into cipher text The brief explanation about the TCHF-AED technique is which in turn decrypted into usable plaintext by attribute presented in forth coming sections. decryption. The encryption and decryption is performed

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Message block

Message block Tiger hash function Hash value (fixed length string) Message block

Fig. 3: Structures of Tiger Cryptographic Hash Function

Cloud data

Hash value(m1) Encrypted cloud Sender data with hash value

Cloud service provider

Compare the hash Recomputed hash value value (m2) of received hash (m1) = hash (m2) encrypted file

Fig. 4: Tiger cryptography based attribute encryption and decryption based upon the Tiger Cryptographic hash function being Attribute Encryption and Decryption: With the help of employed. Tiger hash functions are one way and it the tiger hash function, secret key generation is generates a hash value that is distinctive and is significant role where to ensure the confidentiality of the permanent. Security in cloud service provisioning refers data. Attribute encryption is a type of symmetric to Confidentiality and Availability which is the major encryption in which the secret key of a sender and the issues for Cloud Service Providers. Confidentiality cipher text are depends on attributes. The encryption and refers to prevent the cloud services from the unauthorized decryption is middle on the attributes of cloud user where users. the secret key is generated for each attributes of the data. Figure 4 shows the tiger hash cryptography based Attributes consists of user data such as user location, attribute encryption and decryption which describes the payment plan of the user and occupation of the user. The approach based on Tiger cryptography and the hash original message (i.e. plain text) is encrypted as follows, value. The data stored in the cloud may initially encrypt to produce a cipher text and then hash value is generated plain text = {m, SKey1} for input messages. Whenever the client uses the data (1) stored in the cloud server, the hash value been recomputed using the same hash function to verify the The attribute encryption is used for making plain text correctness of data in the cloud. If the correctness is information (m) with the secret key Skey1. This helps to achieved using comparison, then the cipher text is encrypt the input data with minimum time. After the decrypted to attain the original plaintext at the receiver. encryption, the plain text is converted into cipher text This helps to improve the confidentiality rate. which is expressed as,

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Cipher text = E {m, SKey1} cloud. Initially, the input data is encrypted with secret key (2) and compute the hash value. Then the encrypted data is stored in cloud service provide. When the user access the From (2), the encrypted (E) data is obtained with data from cloud, the hash value is regenerated and secret key. Once the encryption is performed, the hash compares if the two hash value is equal. If the two values value is computed and it stored in cloud server. The tiger are identical, the original message decrypted and it hash function (H)provides a variable-length block of input received to user thereby improving the confidentiality data (m) and therefore it provides the fixed size of the rate. Otherwise, the confidentiality is lost. The algorithmic output hash value. description of Tiger cryptography based attribute encryption and decryption is shown in Figure 5. h(m1) = H(m1) As shown in the Figure 6, the Tiger cryptography (3) based attribute encryption and decryption algorithm is ensured by verifying both the cloud owners and users. From (3), h,(m1) denotes a hash of encrypted data. Followed by this, the cipher text is stored in cloud server. Once the hash value of encrypted data is computed, it The user wants to access the encrypted data; the hash stores the cloud service provider for further processing. value is calculated using same hash function to ensure Whenever the user access the data stored in the cloud, the correctness of data. If the correctness between the the hash value is recomputed using the similar hash hash values is achieved, the attribute decryption is carried function to ensure the correctness of data in the cloud. out. The attribute Decryption is used in TCHF-AED Therefore, the recomputed hash value is calculated as technique decrypts the encrypted message as received to follows, the user. Only upon ensuring that the secret key is held by both the cloud data owners and cloud users are same, h(m2) = H(m2) the decryption process is said to be continued. This helps (4) to increase the confidentiality rate and reduces the communication overhead. In receiver side, comparison between the two hash START values is performed to check the correctness of the data. If the two hash value is equivalent, the decryption is Create cloud environment performed and the original data is obtained to the receiver. with user and CSP Otherwise, the secrecy is lost. Therefore, the cipher text (C)of the data is visible to the receiver using attribute Sender perform encryption and compute decryption. the hash value h (m1) sent to Cloud server

Recompute hash value for received plain text = D {C, SKey1} encrypted file h (m2) (5)

No From (5), D represents the decryption with secret key. If h (m1) = h Confidentiality lost (m2) Therefore, the original plain text is obtained to the receiver with the secret key for both encryption and decryption. Yes Therefore, the tiger hash based attribute encryption and Perform attribute decryption decryption is carried out to improve the confidentiality rate. This helps to improve the secured message Obtain original file to communication in cloud service provisioning with authorize user minimum communication overhead. The flow diagram of End the proposed TCHF-AED technique is illustrated in Figure 5. Figure 5 shows the flow diagram of tiger cryptography based attribute encryption and decryption Fig. 5: Flow diagram of the Tiger cryptography based to provide better security in data communication on the attribute encryption and decryption

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Input: Message ‘M’, Secret Key ‘SKey1’, set of attributes 100KB. Experiment is conducted on factors such as

‘ ’, Cloud Data Owners ‘DOi = DO12,DO ,...,DO n’, Cloud communication overhead, encryption time, memory

Data Requesters ‘DRi = DR12,DR ,...,DRni’, Cloud users ‘CU consumption and confidentiality rate.

= CU12,CU ,...,CUn’ Output: Improved confidentiality rate and reduced RESULT AND DISCUSSION communication overhead Step 1: Begin The analysis of result is carried out between Step 2: For each data request and set of attributes proposed Tiger Cryptographic Hash Function based

Step 3: Perform encryption with SKey1 and compute the Attribute Encryption and Decryption (TCHF-AED) hash function hash function using (2) and (3) technique and existing Key-policy attribute-based Step 4: Encrypted data with hash value stored in cloud encryption (KP-ABE) [1] and Mediated certificate less server public key encryption (mCL-PKE) [2]. The experimental Step 5: Recomputed hash value for the encrypted data analysis is carried out with different parameters such as using (4) communication overhead, encryption time, memory Step 6: If (h(m1)= h(m2) ) then consumption and confidentiality rate compared to the Step 7: Perform attribute decryption with secret key using state-of-the-art works. Performance is evaluated based on (5) to obtain original message following metrics with the help of tables and graph values. Step 8: else Step 9: Confidentiality lost Impact of Communication Overhead: In TCHF-AED Step 10: End if technique, communication overhead is defined as amount Step 11: End for of message lost in a particular timestamp. The formula for Step 12: End communication overhead is expressed as follows,

Fig. 6: Tiger cryptography based attribute encryption M Communication Overhead= no . of users * lost and decryption algorithm time stamp (6)

Experimental Settings: An efficient Tiger Cryptographic From (6), Mlost represents amount of message lost a Hash Function based Attribute Encryption and specified time stamp. It is measured in terms of bits per Decryption (TCHF-AED) technique is experimented using second (bps). Lower the overhead, more efficient the JAVA language and CloudSim simulator for cloud service method is said to be. provisioning. The Amazon Simple Storage Service Table 1 shows the communication overhead (Amazon S3) dataset is used for performing the measurement with respect to different methods Tiger experimental evaluation. Amazon S3 dataset maintains Cryptographic Hash Function based Attribute Encryption data transfer and automatic encryption of data once it is and Decryption (TCHF-AED) technique and existing KP- uploaded in cloud. Amazon S3 is a data warehouse which ABE [1], mCL-PKE [2]. The table shows that the includes images, files and other type of useful communication overhead is reduced in proposed methods information. The Amazon S3 is reliable, fast, less than the existing methods. expensive and scalable for cloud service provisioning. Figure 7 shows the performance of communication Amazon S3 stores data objects on several devices overhead with respect to number of cloud users. From the transversely and allow frequent read and write access to figure, while increasing the number of cloud users, the and from the cloud. The read and write access to these communication overhead gets increased in all the data objects helps to easily obtained required user methods. But comparatively, the TCHF-AED technique information. improves the performance and reduces the communication The TCHF-AED technique performs the experimental overhead. This is due to; Tiger Cryptographic Hash evaluation and compares the results against the existing Function based Attribute Encryption and Decryption Mediated certificate less public key encryption (TCHF-AED) algorithm to encrypt the plain text into (mCL-PKE) [2] with the number of cloud users varied cipher text and computes the hash value. Then the between 10 and 100 and the file size ranging from 10 KB to encrypted data with hash value is sent to cloud server.

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Fig. 7: Measure of Communication overhead

Table 1: Tabulation for Communication Overhead Table 2: Tabulation for encryption time Communication Overhead (bps) Encryption time (ms) ------No. of Cloud Users TCHF-AED KP-ABE mCL-PKE File size (KB) TCHF-AED KP-ABE mCL-PKE 10 4.5 9.4 7.5 10 8.2 15.8 12.3 20 7.8 14.7 12.4 20 12.5 18.9 15.8 30 10.1 18.8 15.7 30 15.3 20.2 18.7 40 12.8 22.7 18.4 40 17.8 23.7 20.4 50 14.6 24.9 20.5 50 20.1 25.8 22.5 60 15.7 26.7 21.1 60 21.8 27.9 24.7 70 19.8 28.3 22.7 70 22.3 31.5 26.8 80 20.5 30.4 24.8 80 24.9 34.6 30.2 90 22.7 32.5 26.7 90 26.7 36.2 33.9 100 28.6 35.8 31.4 100 30.1 38.5 35.7

The user access data from cloud server, the hash value is From (7), Encryption time (ET) is measured in terms of regenerated data for identifying the correctness of the milliseconds (ms). data. If the comparison of hash value is correctly attained, Table 2 shows the comparison results of encryption attribute decryption is performed. In addition, the time for performing the secured data communication using Attribute Decryption decrypts the cipher text on the basis Tiger Cryptographic Hash Function based Attribute of the as acquired by the cloud user. Therefore, the Encryption. The experiments were conducted using decrypted message is obtained and the authorized user different file size as input in the range of 10 to 100 KB. receives the original message thereby reduces the The table clearly illustrates the proposed TCHF-AED communication overhead. The communication overhead technique improves the performance result than the is reduced by 64% and 36% using TCHF-AED technique existing KP-ABE [1], mCL-PKE [2]. compared to existing KP-ABE [1], mCL-PKE [2] Figure 8 depicts the impact of encryption time taken respectively. on improving the secured message communication for different file size. All the results provided in Figure 7 Impact of Encryption Time: Encryption time is defined as shows that the proposed TCHF-AED technique the amount of time taken to perform the encryption for significantly outperforms than the two existing methods, secured data communication in cloud service KP-ABE [1], mCL-PKE [2]. While increasing the file size, provisioning. The formula for encryption time is the encryption time gets increased in all the methods. But formulated as follows, the proposed TCHF-AED technique improves the secured message communication with minimum encryption time. Encryption time = Encryption end time – Encryption start This is because, the tiger hash based attribute encryption time (7) is performed to convert the original message into cipher

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Fig. 8: Measure of Encryption time

Table 3: Tabulation for Memory consumption In the experimental setup, the file size is taken for Memory consumption (KB) input to perform the memory consumption. The results of ------memory consumption are listed in table 3.TheTCHF-AED File size (KB) TCHF-AED KP-ABE mCL-PKE 10 96 124 114 technique measures the security rate on message 20 107 138 127 communication while providing multiple attributes 30 112 142 137 information to the cloud server. Therefore, the proposed 40 124 155 144 TCHF-AED technique consumed less memory for 50 131 167 156 reducing the complexity than the state-of-the-art methods 60 146 173 163 KP-ABE [1], mCL-PKE [2]. 70 152 195 179 80 163 210 186 The result analysis of memory consumption with 90 178 224 194 respect to file size is shown in figure 9. From the figure, 100 186 240 210 the number of files taken in the range of 10 KB to 100KB by 10 to 100 cloud users as the input to measure memory text and hash value for improving the security in data consumption in cloud environment. The figure clearly communication in cloud services. The attribute encryption shows the TCHF-AED technique utilizes the less amount is carried out in TCHF-AED technique considers an of memory than the other Methods [1] [2]. While Attributes which includes user location and payment plan increasing the number of files, the memory consumption of the user. Through the encryption, the original text is is increased in all the methods. This process is repeated converted to cipher text with secret key on order to up to 100 KB of file as input. Therefore, the storage space improve the security. Furthermore, the TCHF-AED required for file is reduced in TCHF-AED technique. This technique improves the secured message communication is because; the tiger hash function works well for between the cloud users and reducing the encryption time database storage in an efficient manner. The table is used by 41% compared to KP-ABE [1] and 23 % compared to in TCHF-AED technique for storing all the input files. mCL-PKE [2]respectively. Therefore, this helps to reduce the complexity exists during message communication in cloud service Impact of Memory Consumption: Memory consumption provisioning. As a result, TCHF-AED technique utilizes is defined as the difference between the total memory the less memory consumption and it reduced by 27% space for storing the multiple messages and the unused compared to existing KP-ABE [1] and also reduced by memory. The mathematical formulation of memory 16% than the mCL-PKE [2] methods respectively. consumption is as given below, Impact of Confidentiality Rate: In TCHF-AED technique, MC = Total memory for storing the multiple messages – the confidentiality rate is achieved during the secure unsed memory (8) message communication using tiger hash cryptography. Confidentiality rate is defined as the ability of the system From (8), the memory consumption ‘MC’ is measured to protect message being transmitted and only the in terms of kilo bytes (KB). Lower the memory authorized user received the message from cloud server. consumption more efficient the method is said to be. The confidentiality rate is measured in percentage (%).

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Fig. 9: Measure of memory consumption

Fig. 10: Measure of confidentiality rate

Table 4: Tabulation for Confidentiality rate clients to server. The requested attribute from the client is Confidentiality rate (%) only observable from the cloud storage with high security ------level from the cloud server. Therefore, the TCHF-AED File size (KB) TCHF-AED KP-ABE mCL-PKE 10 80.65 72.24 75.52 technique increases the confidentiality rate than the other 20 82.31 74.85 78.65 methods [1] [2]. In TCHF-AED technique, the attributes 30 84.52 77.48 80.24 encryption and decryption is carried out with the help of 40 85.75 78.14 81.55 tiger hash cryptographic function achieves higher 50 87.69 79.10 82.67 confidentiality rate. Each message communication is 60 88.63 80.12 83.68 equipped with higher confidentiality rate with the help of 70 90.35 81.32 84.52 80 93.54 82.20 85.12 attribute encryption and decryption. Furthermore, the 90 94.58 83.41 86.47 TCHF-AED technique provides high services to improve 100 95.74 84.73 87.84 the message communication in cloud service provisioning. Therefore, this helps to improve the Table 4 illustrates the performance of confidentiality rate confidentiality rate in cloud service provisioning. In provides the number of input files in cloud services. The addition, the hash value is computed for all the input confidentiality is measured between proposed TCHF-AED values and it’s encrypted. Then the encrypted data with technique and existing KP-ABE [1], mCL-PKE [2] with hash value are stored in cloud server. When the user Amazon S3 dataset. The confidentiality rateis increased in access data from cloud, the hash value is recomputed and the TCHF-AED technique, compared to existing methods. achieves the correctness. If the correctness is achieved, The confidentiality rateof the proposed technique and the attribute decryption is performed thereby improving existing methods is shown in figure 9. the confidentiality rate. Then the original message Figure 10 clearly shows the analysis of decrypted and it received to authorized user. Therefore, confidentiality rate during the message communication the confidentiality rate is increased by 10% and 6% using between the cloud users and server. In message TCHF-AED technique when compared to existing KP- communication, the attributes requests are sent from the ABE [1], mCL-PKE [2] method respectively.

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As a result, Tiger Cryptographic Hash Function security problem in cloud environment. However, the based Attribute Encryption and Decryption (TCHF-AED) efficiency of encryption and decryption process is not technique provides the improved results in secured efficient. TCHF-AED technique performs attribute message communication. encryption and decryption based on the hash function to improve the security. In order to provide the secure and Related Works: A secure and effective data collaboration efficient data access control in P2P storage cloud [20] to scheme was presented in [11] based on attribute-based allow the data owner to assign file encryption. Though encryption (ABE) and attribute-based signature (ABS). the method reduces the computation overhead and it However, the data synchronization is difficult in data failed to achieve the confidentiality. Therefore, the collaboration. The tiger hash cryptographic hash function TCHF-AED technique achieves better confidentiality rate provides the better data management in cloud service through the tiger cryptographic hash function. As a provisioning. In [12], the proposed secure model was result, the proposed Tiger Cryptography Hash Function established for improving the security of allservices. based Attribute Encryption and Decryption technique But the security mechanism is not efficient to provide the achieves higher confidentiality rate in cloud service cloud services. The TCHF-AED technique performs provisioning. efficient attribute encryption and decryption to improve the secure communication. In [13], Security-Aware CONCLUSION Efficient Distributed Storage method was introduced but it provides security for data replication as well. The An efficient Tiger Cryptographic Hash Function TCHF-AED avoids the data replication and improves the based Attribute Encryption and Decryption (TCHF- secured message communication. An efficiently multiuser AED)technique is introduced for secured message searchable attribute-based encryption method was communication in cloud service provisioning. Initially, the introduced in [14] but the time taken for performing the client request is the number of attributes sends to cloud encryption is remained unsolved. This issue is addressed server. Tiger cryptographic hash function takes an input in TCHF-AED technique. A number of well-known as message block and attains a string of any length as cryptographic protocols was presented in [15] for input and produces a fixed length string as output which encrypting the data that perform a secure communication is called as hash value. Based on, the attribute encryption for clouds. However, the method failed to perform the is performed for attaining the encrypted data and encryption for securing the data communication. The computed its hash value for ensuring the secrecy of data. TCHF-AED technique performs encryption and The encrypted data with hash value is stored in cloud decryption to improve confidentiality. An efficient, flexible server for further processing. The user access the data and anonymous data sharing protocol was designed in from cloud, the hash value is recomputed and performs [16] for data sharing in cloud computing. But the data the comparison to obtain the confidentiality. If the storage ability of the protocol is failed. TCHF-AED comparison is performed correctly, the confidentiality is technique consumes less storage space for number of archived and performed the attribute decryption. Attribute input file. decryption is used to decrypts the encrypted message as Security as a service model [17] guarantees a possessed by authorized user. Only the secret key is baseline security to the cloud service provider for similar for both the cloud data owners and cloud users, protecting the individual cloud infrastructure. However, the decryption process is continued and the original the various types of attacks are occurred. The TCHF-AED message is obtained to the authorized user thereby technique uses a tiger hash function which is collision- increasing the confidentiality rate. Experimental evaluation free hence it reduces the attacks. In order to prevent the is carried out to measure the communication overhead, unauthorized access, files are encrypted using RSA encryption time, memory consumption and confidentiality algorithm [18] and MD5 message digest is used for rate. The performance results show that the proposed generating the digital finger print. Though, the method TCHF-AED technique considerably increases the still has security and confidentiality about their stored confidentiality rate and reduces the encryption time and data. TCHF-AED technique improves the confidentiality memory utilization. The TCHF-AED technique guarantees of the data to prevent the unauthorized user. A Cipher text the secured message communication with lesser Policy Attribute-Based Encryption (CP-ABE) based data communication overhead than the state-of-the-art sharing scheme was presented in [19] to handle the methods.

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